With the quick development in the electronic industry in recent years, many electronic devices have highly upgraded performance and more internal chip sets with constantly increased computing and data processing speed. However, the increased internal chip sets also produce more heat during operation thereof. The produced heat must be timely removed, lest it should adversely affect the electronic devices' performance and computing speed. The electronic devices might become burned out if the produced heat is undesirably accumulated therein. Therefore, it has become an important issue as how to effectively dissipate heat from the electronic devices.
A cooling fan has become one of the prerequisite parts in many heat dissipating systems because it is able to quickly carry away the heat absorbed by and then radiated into ambient air by radiating fins and to ensure good air circulation surrounding an electronic device.
In FIGS. 1A and 1B, there is shown a conventional motor stator structure 10 for use with a cooling fan. The motor stator structure 10 includes a plurality of silicon steel plates 11, each of which has a central hole 111 and a plurality of magnetic poles 112 symmetrically and radially outward extended from the central hole 111. When the silicon steel plates 11 are stacked, the magnetic poles thereof are also correspondingly stacked to form a plurality of magnetic-pole columns 113. A plurality of windings 12 are wound on the magnetic-pole columns 113. A space 121 is formed between any two adjacent magnetic-pole columns 113. A covering 13 is filled into the spaces 121 and encloses the silicon steel plates 11, the magnetic-pole columns 113, and the windings 12 therein by way of injection molding. When the motor stator structure 10 operates, the silicon steel plates 11 and the windings 12 will generate a magnetic field. In the process of generating the magnetic field, the temperature of the silicon steel plates 11 and the windings 12 increases to produce heat in the motor stator structure 10. Since the conventional motor stator structure 10 does not include any heat dissipation device around the silicon steel plates 11 and the windings 12, the produced heat will accumulate in the motor stator structure 10 and could not be effectively transferred to an outer side of the covering 13 for dissipating into ambient air. The accumulated heat will adversely affect the operating performance of the cooling fan, preventing the cooling fan from effectively extend its heat dissipation characteristic.
In brief, the conventional motor stator has the following disadvantages: (1) unable to effectively remove the heat produced by the windings and the silicon steel plates from the stator; (2) adversely affecting the cooling fan's operating performance; and (3) unable to effectively extend the fan's heat dissipation characteristic.